全文获取类型
收费全文 | 5478篇 |
免费 | 359篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 126篇 |
儿科学 | 137篇 |
妇产科学 | 126篇 |
基础医学 | 856篇 |
口腔科学 | 174篇 |
临床医学 | 489篇 |
内科学 | 1059篇 |
皮肤病学 | 96篇 |
神经病学 | 350篇 |
特种医学 | 149篇 |
外国民族医学 | 3篇 |
外科学 | 849篇 |
综合类 | 98篇 |
一般理论 | 4篇 |
预防医学 | 341篇 |
眼科学 | 141篇 |
药学 | 467篇 |
中国医学 | 53篇 |
肿瘤学 | 350篇 |
出版年
2024年 | 5篇 |
2023年 | 62篇 |
2022年 | 154篇 |
2021年 | 236篇 |
2020年 | 147篇 |
2019年 | 193篇 |
2018年 | 254篇 |
2017年 | 157篇 |
2016年 | 185篇 |
2015年 | 200篇 |
2014年 | 278篇 |
2013年 | 332篇 |
2012年 | 557篇 |
2011年 | 485篇 |
2010年 | 252篇 |
2009年 | 194篇 |
2008年 | 292篇 |
2007年 | 301篇 |
2006年 | 267篇 |
2005年 | 233篇 |
2004年 | 193篇 |
2003年 | 190篇 |
2002年 | 173篇 |
2001年 | 59篇 |
2000年 | 53篇 |
1999年 | 43篇 |
1998年 | 42篇 |
1997年 | 24篇 |
1996年 | 25篇 |
1995年 | 14篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 23篇 |
1991年 | 23篇 |
1990年 | 16篇 |
1989年 | 17篇 |
1988年 | 21篇 |
1987年 | 22篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1972年 | 3篇 |
1971年 | 4篇 |
排序方式: 共有5868条查询结果,搜索用时 15 毫秒
81.
Background : Viral kinetics suggests that daily administration of α‐interferon (IFN) will clear hepatitis C virus (HCV) RNA earlier and more frequently compared with standard t.i.w. To reduce the likelihood of viral replication, mutation and subsequent development of resistance, daily dosing with IFN may be appropriate. To determine the safety and efficacy of daily IFN with ribavirin in chronic HCV infection we performed a prospective study. Methods : Thirty‐five naïve adult HCV‐positive patients (25 male/10 female) were treated with IFN‐α2b; 5 MU daily for 2 weeks followed by 3 MU daily for 22 weeks and ribavirin 800–1200 mg/day depending on weight. Liver biopsy, performed in 25 patients, showed mild to moderate activity in 19 patients (76%) and severe activity in six patients (24%). Two patients showed staged IV fibrosis. Serotyping was performed in 29 patients by an enzyme immunoassay‐based Murex assay. Type 3 was the predominant serotype, present in 14 cases. Hepatitis C virus RNA was measured by the Chiron bDNA assay. Results : Mean baseline HCV‐RNA level was 14.2 ± 18.7 MEq/mL (median 6.09; range 0.2–92.5), which became undetectable in all but three patients at week 4. Normalization of alanine aminotransferase (ALT) at week 4 was seen in 27 patients. Three patients withdrew due to non‐compliance. Thirty‐two patients completed 24 weeks of therapy as per the protocol. At the end of treatment, the HCV‐RNA level was negative in 29 of 32 patients (90.6%) and ALT was normal in 31 of 32 patients (97%). Sustained viral response at 6 months follow up was seen in 28 of 32 patients (88%). The ALT level was normal in 28 of 32 patients (88%). Conclusion : Daily administration of IFN with ribavirin is well tolerated in the majority of patients. There is rapid elimination of virus with normalization of ALT and a significantly high sustained viral response. © 2002 Blackwell Publishing Asia Pty Ltd 相似文献
82.
Natalie J. Frost Michael Weinborn Gilles E. Gignac Stephanie R. Rainey-Smith Shaun Markovic Nicole Gordon Hamid R. Sohrabi Simon M. Laws Ralph N. Martins Jeremiah J. Peiffer Belinda M. Brown 《The American journal of geriatric psychiatry》2021,29(2):129-140
BackgroundThere is a paucity of interventional research that systematically assesses the role of exercise intensity and cardiorespiratory fitness, and their relationship with executive function in older adults. To address this limitation, we have examined the effect of a systematically manipulated exercise intervention on executive function.MethodsNinety-nine cognitively normal participants (age = 69.10 ± 5.2 years; n = 54 female) were randomized into either a high-intensity cycle-based exercise, moderate-intensity cycle-based exercise, or no-intervention control group. All participants underwent neuropsychological testing and fitness assessment at baseline (preintervention), 6-month follow-up (postintervention), and 12-month postintervention. Executive function was measured comprehensively, including measures of each subdomain: Shifting, Updating/ Working Memory, Inhibition, Verbal Generativity, and Nonverbal Reasoning. Cardiorespiratory fitness was measured by analysis of peak aerobic capacity; VO2peak.ResultsFirst, the exercise intervention was found to increase cardiorespiratory fitness (VO2peak) in the intervention groups, in comparison to the control group (F =10.40, p≤0.01). However, the authors failed to find mean differences in executive function scores between the high-intensity, moderate intensity, or inactive control group. On the basis of change scores, cardiorespiratory fitness was found to associate positively with the executive function (EF) subdomains of Updating/Working Memory (β = 0.37, p = 0.01, r = 0.34) and Verbal Generativity (β = 0.30, p = 0.03, r = 0.28) for intervention, but not control participants.ConclusionAt the aggregate level, the authors failed to find evidence that 6-months of high-intensity aerobic exercise improves EF in older adults. However, it remains possible that individual differences in experimentally induced changes in cardiorespiratory fitness may be associated with changes in Updating/ Working Memory and Verbal Generativity. 相似文献
83.
Lewis H Mervin Ekaterina Mitricheva Nikos K Logothetis Angelo Bifone Andreas Bender Hamid R Noori 《Journal of cerebral blood flow and metabolism》2021,41(4):874
Functional magnetic resonance imaging (fMRI) is an extensively used method for the investigation of normal and pathological brain function. In particular, fMRI has been used to characterize spatiotemporal hemodynamic response to pharmacological challenges as a non-invasive readout of neuronal activity. However, the mechanisms underlying regional signal changes are yet unclear. In this study, we use a meta-analytic approach to converge data from microdialysis experiments with relative cerebral blood volume (rCBV) changes following acute administration of neuropsychiatric drugs in adult male rats. At whole-brain level, the functional response patterns show very weak correlation with neurochemical alterations, while for numerous brain areas a strong positive correlation with noradrenaline release exists. At a local scale of individual brain regions, the rCBV response to neurotransmitters is anatomically heterogeneous and, importantly, based on a complex interplay of different neurotransmitters that often exert opposing effects, thus providing a mechanism for regulating and fine tuning hemodynamic responses in specific regions. 相似文献
84.
A Recessively Inherited Risk Locus on Chromosome 13q22-31 Conferring Susceptibility to Schizophrenia
Tariq Mahmood Mohammed E El-Asrag James A Poulter Alastair G Cardno Anneka Tomlinson Sophia Ahmed Ahmed Al-Amri Jamshid Nazari Joanna Neill Rifka S Chamali Nancy Kiwan Suhaila Ghuloum Hamid A Alhaj Juliette Randerson Moor Shabana Khan Hassen Al-Amin Colin A Johnson Peter Woodruff Iain D Wilkinson Manir Ali Steven J Clapcote Chris F Inglehearn 《Schizophrenia bulletin》2021,47(3):796
85.
86.
87.
88.
The present study deals with designing and synthesizing novel dyes using the drug combination of edaravone and azo compounds which can be used as an indicator for anions and cations. The desired product synthesis was accomplished via a two-step process involving diazotizing the aromatic amines followed by the resultant salts coupling with edaravone. The resulting dyes were obtained with high yields under mild conditions. The structures of the dyes were identified with UV-vis, FT-IR, 1H NMR and 13C NMR spectra and CHN analysis. To investigate the solvatochromism effect, the interaction of different solvents with the selected dyes was evaluated using several parameters including the dielectric constant, refractive index, hydrogen bond donating ability, hydrogen bond accepting ability and dipolarity/polarizability scale. To achieve deep understanding about the stability and geometrical characteristics of the azo–hydrazo tautomers of the synthesized dyes and their UV-visible spectra prediction, some DFT calculations were also carried out on the synthesized dyes. The antibacterial activities of some synthesized compounds were also evaluated using the disk diffusion method. The results revealed different activity of the selected synthesized dyes for antibacterial tests against selected Gram positive and Gram negative bacteria.The present study deals with designing and synthesizing novel dyes using the drug combination of edaravone and azo compounds which can be used as an indicator for anions and cations. 相似文献
89.
Shannon J Ernst P Yamauchi Y Olivenstein R Lemiere C Foley S Cicora L Ludwig M Hamid Q Martin JG 《Chest》2008,133(2):420-426
BACKGROUND: Some studies of severe asthma suggest that persistence or alteration in the pattern of inflammation may be associated with the severity of the disease. Whether there are differences in the expression of the principal cytokines and chemokines relevant to eosinophilic and neutrophilic inflammation in the airway tissues of severe compared to moderate asthmatics has not been determined. The aim of this study was to compare the patterns of expression of representative T-helper (Th) type 1 (interferon [IFN]-gamma) and Th-2 cytokines (interleukin [IL]-4, IL-5) and the neutrophil- and eosinophil-associated chemokines (IL-8 and eotaxin) in the airway tissues of patients with severe and moderate asthma. METHODS: Subjects with severe asthma (n = 24) and a comparison moderate asthma group (n = 26) were assessed using spirometry, induced sputum, exhaled nitric oxide, and bronchial biopsy. The expression of proteins of interest in the epithelium and subepithelium of the airway wall was examined by immunocytochemistry. RESULTS: Subjects with severe asthma were more symptomatic, had a lower FEV(1), and had more sputum neutrophilia (p = 0.007) and eosinophilia (p = 0.001). Exhaled nitric oxide was similar between groups. IL-8 and IFN-gamma expression were increased and IL-4 expression was decreased in severe asthma compared to moderate disease (p < 0.001 for each comparison). Eotaxin and IL-5 expression did not differ between the groups. CONCLUSION: Patients with severe asthma have increases in neutrophils and eosinophils in the sputum, and differ in airway cytokine/chemokine expression from moderate asthmatics. Excess neutrophilia may be explained by increased expression of IL-8, but differences in eosinophilia do not appear to be associated with IL-5 and eotaxin expression. 相似文献
90.
Seyyed Hamid Hashemi Fariba Keramat Mitra Ranjbar Mojgan Mamani Ali Farzam Shirin Jamal-Omidi 《International journal of infectious diseases》2007,11(6):496-500
OBJECTIVE: To determine the frequency and clinical characteristics of osteoarticular complications of brucellosis in an endemic region in Iran. METHODS: In a prospective study we evaluated 245 patients with brucellosis diagnosed between January 2004 and December 2005. Patients included were those older than 8 years of age and who had clinical features suggestive of brucellosis and specific antibodies at significant titers, and/or positive blood or body fluid culture for Brucella species. A bone scan was performed in those with a clinical suspicion of osteoarticular involvement. RESULTS: Seventy patients (28.6%) had osteoarticular complications. Sacroiliitis was the most common complication (75.7%), followed by spondylitis (21.4%) and peripheral arthritis (8.6%). Spondylitis was the most common osteoarticular complication in the elderly. Relapses occurred in five (2%) patients, three of them with spondylitis. CONCLUSIONS: Osteoarticular disease is the most common complication of brucellosis in Western Iran. Sacroiliitis is the most common form of osteoarticular complication. With the use of a proper treatment regimen, the prospect for recovery is good. 相似文献